Submersible pumps are often installed in underground tanks or sumps that handle hazardous liquids or contaminated liquids such as sewage. In the past, maintenance of such pumps required drainage of the sump followed by a maintenance person descending into the sump to work on the submersible pump. More recently, lift out slide rail systems have been used. These systems have lift out couplings and permit removal of the pumps from sumps or underground tanks without having to drain the sump and without having to conduct maintenance on the pump in place. A coupling is provided which has substantially vertical flanges, one portion of the coupling being connected by pipes to the pump and the other portion of the coupling connected to an outlet pipe extending upwards from the sump. A lifting arrangement is attached to the pump and lift out portion of the coupling so the pump may be lifted out of the sump. As the lift out portion of the coupling moves up, the movable flange breaks away from the opposing fixed flange; the pump is lifted on guide rails and removed from the sump for maintenance. For installation, the pump is lowered on the guide rails until the movable flange of the coupling mates with the opposing fixed flange, thus connecting the pump to the discharge pipe.
In the past a majority of these submersible pumps were specially made with horizontal discharges to match the lift out couplings. Examples of these types of pumps and couplings are shown in U.S. Pat. No. 4,060,345 to Blum, U.S. Pat. No. 4,564,041 to Kramer, U.S. Pat. No. 4,661,047 to Weis and U.S. Pat. No. 4,679,991 to Harbison et. al.
Many submersible pumps have upward discharges with flanged connections and elbows are therefore required to connect the pump to the couplings which generally have mating flanges that are vertical or nearly vertical. Examples of these types of arrangements are shown in U.S. Pat. No. 3,592,564 to Conery and U.S. Pat. No. 4,392,790 to Shibata et. al.
Most standard submersible pumps today are being made with an upward facing threaded discharge, the pipe sizes generally range from 11/4" up to about 3", and in order to use such a pump with a lift out coupling it has been necessary to first of all provide a pipe of sufficient length that it extends above the pump itself, otherwise it has not been possible to screw an elbow into the threaded discharge outlet. An example of such an arrangement is shown in U.S. Pat. No. 4,886,426 to Surinak. The reason the standard elbows cannot be rotated in the threaded outlet is because the standard elbow hits the pump when it is rotated.
When a submersible pump has an extension pipe so the lift out coupling is positioned above the pump, it becomes difficult to keep the pump and coupling in exactly the right attitude when being lowered on guide rails and this can result in difficulties in mating the two halves of the coupling to form a seal.
It is an aim of the present invention to provide a lift out coupling for a submersible pump that connects to an upward facing threaded discharge of standard submersible pumps available on the market today, the coupling arranged to be as close to the upward facing discharge as is reasonably possible and not extending above the pump itself. Furthermore, the coupling is of sufficient strength so that it can support the pump above the base of a tank or sump, thus avoiding difficulties of solid particles on the base causing an obstruction when a pump is replaced.
It is a further aim to provide a lift out coupling for a submersible pump that has a limited number of components and fits standard submersible pumps with upward facing threaded discharges of 11/4", 11/2", 2" and 3". Furthermore, the lift out coupling has a close quarter elbow, threaded at one end, that can be screwed into the threaded discharge outlet of the pump and can be rotated in the outlet without interfering with the pump or the motor of the pump.
It is a further aim of the present invention to provide a submersible pump lift out coupling having connection to a lift arrangement such as a lift out chain or the like that can be arranged to hold the pump and coupling substantially level when being raised on guide rails within the sump or tank.